Soil resistant textile material and method of making the same



U States flic 2,876,140 Patented Mar. 3, 1959 son. METHOD OF MAKING THESAME 2 duction of a cationic softening agent and carboxymethyl cellulosealong with the M80 greatly increases soil resistance and improveslaunderability to the point where it is substantially unimpaired. Thetreatment, further- 5 more, improves the luster of the material and doesnot Robert E. simian. 6a.,- s a nor to an, Mann factoring company,Macon,- Gm, a corporation of Georgi:

This invention relates to teittile materials having improved soilresistant properties and process for making same.

Various methods have been employed or suggested for increasingresistance to soiling of woven fabrics, such as clothing, drapery andupholstery materials, and the like; These treatments generally take thefoi'in of filling the interstices of the raunwiihjesinon compounds or ofapplying a thick, smooth surface to the fabric. For the most part, theseprocedures sutfen from various disadvantages such as causing matting ofthe fibers, adversely affecting the feel of the fabric and tenaciouslyretaining soil during laundering operations. The treatments have been ofno value for use with pile or loop fabrics such as rugs'where'j'rn'atting of the fibers cannot be tolerated.

The object of this invention isto provide a process for treating textilematerials which markedly increases resistance to soiling withoutadversely afiectin'g' launderability or the physical characteristics ofthe fibers or fabric. 0 I v Another object: i's-v to providefa processfor increasing soil resistance which is particularly advantageous foruse with pile or loop fabrics such as rugs and carpeting.

Other objects and advantages of the invention will become obviousfrom'the following detailed description.

My process is particularly suitable for use with textile materialscomprising vegetable and/or synthetic fibers, suchas cotton, viscose and'a'cetate ia'yons, nylon and the like, which are particularlysusceptible to oiling and which hold the soiltenacious'ly so that nojfalhome cleaning treatments scenes-vacuuming ineffective in removingthdirt. My treatment can also be efiic'aciously applied to wool althoughwool possesses considerable natural soil-resistantpropei'ties ascompared with vegetable and synthetic fibers. It is especiallyadvantageous for application to wool blends with vegetable and/orsynthetic fibers. The treatment can be applied to the raw stock fiber,yarn or finished goods such as rugs, clothing, drapery and upholsterymaterial.

Broadly speaking my process comprises impregnating the fiber, yarnorfabric with barium sulfate foi'rne'd in situ, a cationic softening agentand ca'rboxymethyl u -Q I have found that BaSOq, when foi'rned in sitnso that it is deposited the interstiees of the fiber and fabric, impartssome soil resistance to the material. However, this advantage is off-setby the fact that the soil which does attach itself to the material aftersuch treatment is held vary tenaciously, is resistant to vacuuming andbe removed only to a very limited extent by laundering. I have that theintroadversely affect feel or texture. There is no matting or stickingof the fibers so that the treatment is particularly suitable for usewith loop or pile fabrics such as rugs.

As aforementioned, the BaSO; should be formed in situ. This can beaccomplished by separately impreghating the material with a solution ofa soluble barium salt, such as the chloride or acetate, and a solutionof a soluble sulfate such as sodium, potassium or magnesium sulfate toprecipitate BaSO, in very finely divided form directly into theinterstices and crannies of the fibers, yarn or fabric. The saltsolutions can be applied in any desired sequence. Preferably thematerial is dried prior to impregnation with the second solution. Forsatisfactory performance, it is generally desirable to incorporate atleast about 2% and, preferably, about 3% of BaSO based on the weight ofthe material. There is no critical upper limit of BaSO; added, althoughat amounts above about 10%, the increase in soil-resistance maygenerally not be sufiic'iently appreciable to warrant the increasedcost.

' The impregnating solutions employed to deposit the BaS0 can be of anyconcentration up to the limit of solubility of the reacting salt so longas the amount of salt is adequate for the desired pick-up and the amountof solution is sufiicient for thorough impregnation of the material. Itis generally desirable to employ a somewhat higher concentration of saltin the second solution to ensure as complete reaction as possible.

impregnation of the material can be carried out at anydesiredtemperatur'eas, for example, room temperature, although, somewhatelevated temperatures, e. g. about to 200 F., facilitate more rapidpenetration of the material.

I have found that softening agents of the higher fatty acid amide typewhich are cationic at the time of addition or become cationic duringprocessing, namely as a result of the acidification subsequently to bediscussed,

are particularly suitable for my purpose. A number of I r-o-n,Nn--ti-Nn-m-ot:R1t:--/ wherein R is 'a hydrocarbon residueresulting from a polycarboxylic acid, R and R are simple alkylene groupsof from 2 to 3 carbons. Attached to one of the carbons in R, and R is anacid amide side chain of the general formula:

0 Rt- NH[( H|)w-NHLCHr-] wherein R is hydrocarbon, e is an integer offrom 0 to 4 and m is an integer of from 2 to 3. To increase watersolubility or dispersibility these compounds can be treated with an acidto form an acid salt or they can be alkylated. Formation of the acidsalt also converts compounds of this type which are not alreadycationic, such as Ahcovel R, into the cationic state.

Other fatty acid amide cationic softeners which I have also foundsatisfactory include ester-amides, which are condensation products of adihydroxy-alkyl amine and a higher aliphatic acid. Such products areavail able commercially as, for example, Finish 100-X.

For satisfactory results the cationic softening agent should beincorporated in an amount comprising at least about 0.1 preferablyabout0.25%, based on the weight of the material. Optimum range is about 0.25to 1.0%. As much more can be introduced as desired but, generallyspeaking, at amounts above about 2 to 3% there is little advantage to begained to warrant the increased cost.

The carboxymethyl cellulose, which I prefer to employ in the form of itsalkali metal salt such as the sodium salt, is desirably added in anamount comprising at least about 0.1% of the material, optimum rangebeing about 0.25 to 2.0%. There is no critical upper limit but. in mostcases, there is little economic advantage with additions above about 3to 5%.

The cationic softening agent and the carboxymethyl cellulose can beintroduced into the material, e. g., fibers, yarn or fabric, byexhaustion from an aqueous solution after impregnation of the materialwith the B2180, or can be added along with the second reaction solutionemployed for formingthe BaSO, in situ. I prefer to use the latterprocedure because of its convenience in eliminating an additionalprocessing step.

Concentration of the softening agent and carboxymethyl cellulose in theaqueous treating bath is not criti- -cal'.' It is essential only to havesufiicient present in the aqueous solution to obtain the desired degreeof exhaustion on to the material. The treating bath may be maintained atordinary or somewhat elevated temperatures. At temperatures of about 100to 200 F., the material is more easily and rapidly penetrated by thesolution so that the use of such elevated temperatures is a practicalmeans for expediting processing.

Exhaustion of a fatty acid amide softening agent and the carboxymethylcellulose from aqueous solution is best accomplished in an acidmediumproduced by the addition of an organic acid, such as acetic acid,in sufficient amount to lower the pH to about 6.5 or less. Where thecarboxymethyl cellulose is added to the treating bath in .the form ofits sodium salt, it is exhausted ontothe fibers as the parent compoundwith the sodium remaining in solution as a salt of the acidifyingorganic acid.

I have found that more complete exhaustion of the softening agent andcarboxymethyl cellulose from the treating bath and more uniformdistribution on the material are obtained when the pH is first reducedgradually by means of an acid salt, such as magnesium sulfate, aluminumsulfate or the like, in suflicient amount to bring the pH down to about7.0 or less, preferably about 6.5, and then further reduced by additionof sufficient organic acid, such as acetic acid, to bring it to thedesired level of 6.5 or less, preferably about 6.0 to 6.5. Although Iprefer to use acetic acid because of its relatively low cost, otherorganic acids, such as propionic acid, succinic acid and the like canalso. be used.

Where the softening agent and the carboxymethyl cellulose are introducedin the bath containing the second reaction component for formation ofthe BaSO, in the material, it is advisable to agitate the material withthe aqueous solution for several minutes to accomplish BaSO. formationin the material before addition of the acid salt to exhaust thesoftening agent and carboxymethyl cellulose. The gradual lowering of thepH by the acid salt to the desired level is generally accomplishedwithin several minutes, e. g. about 5 minutes, and the organic acid canthen be added in requisite amount to produce the desired acidity. Thematerial can then be removed from the aqueous treating bath and dried.

The treatment of the material, e. g. fibers, yarn or fabric, can becarried out in any suitable device or machine, such as dyeing or laundryequipment, which provides suflicient agitation for thorough impregnationof the material with the treating solutions. Drying similarly can beperformed with any suitable, standard equipment.

The-soil-proofing treatment aforedescribed can be car ried out in wholeor in part at any stage in the fabrication of the textile material. Itcan be applied to the raw stock fiber, to the yarn or to the finishedfabric, e. g. woven, pile or loop fabric such as clothing, drapery orupholstery materials or rugs. The BaSO; or one component such as thebarium or sulfate salt can be deposited at one stage, e. g. the fiber oryarn, and the rest of treatment completed on the finished fabric.

EXAMPLE I A white cut pile rug made with viscose rayon yarn, comprising8 denier, 1%; inch fibers, on a cotton backing was treated in alaundry-type machine with a solution comprising 1 part barium chlorideto 9 parts water at 110 F. for 15 minutes. The ratio by weight of bariumchloride solution to material was 30:1. The material was extracted to awet pick-up and dried at a temperature of 200 F. The resulting bariumchloride pick-up was 10% by weight.

The dried material was then treated with 30 parts by weight of anaqueous solution containing 15% by weight of the material'of sodiumsulfate, 2% by weight of the material of Ahcovel R, which comprises 30%by weight of the solid fatty amide polymer, and 2% by weight ofthe'material of sodium carboxymethyl cellulose at F. for 5 minutes. 2%magnesium sulfate by weight of the material was then added to thesolution and treatment continued for 5 more minutes. 1% by weight of thematerial of 56% acetic acid was added to the bath and agitation of thematerial continued for 5 more minutes. The material was then extractedand dried. The final pH was about 6.2. Solids pick-up of the driedmaterial was 9.2% barium sulfate, 0.5% Ahcovel R and 0.5 carboxymethylcellulose.

EXAMPLE II Raw stock viscose rayon fibers were treated at F. for 20minutes in a raw stock pressure dyeing machine with a 5% aqueous bariumchloride solution. Weight of solution to fibers was 10:]. The treatedfibers were extracted to an 80% wet pick-up and dried in a stock dryer.Barium chloride pick-up was 4% by weight of the fibers.

The fibers were then processed into yarn and made into cut pile rugs ona cotton backing. The rugs were placed in an agitation-type launderingmachine and treated at 110 F. for 5 minutes with an aqueous solutioncontaining 15% sodium sulfate by weight of the material and 2% sodiumcarboxymethyl cellulose by weight of the material. 2% magnesium sulfateby weight of the material was then added and treatment continued for 5more minutes. 1% of 56% acetic acid by weight of the material was addedand agitation continued 5 minutes longer. The material was thenextracted and dried to give a solids pick-up of 3.78% barium sulfate,0.5% Ahcovel R and 0.5 carboxymethyl cellulose. Final pH was about 6.2.

EXAMPLE III A cut pile rug made of a nylon and rayon blend on a cottonbacking was treated as in Example I except that the temperature of thetreating solutions was maintained at 200 F, Solids pick-up was the same.

EXAMPLE iv Soiling of the samples was accomplished by wrapping themaround a screen mesh cylinder in a soiling drum, charging the drum witha weighed amount of the soiling composition and then revolving the drumfor 30 minutes. The 30 minute exposure under these conditions isequivalent to about 8 months exposure in a large business oflice. Aftereach 30 minute soiling cycle, the rugs were vacuum cleaned and lightreflectance measured in terms of photovolt readings on a reflectometer.

The rugs were laundered in a tumbler type laundering machine using 2%olive soap flakes based on the weight of the fabric. They were washedfor minutes at 140 F., rinsed, extracted and dried.

Table I Reflec- Retlee- Raduc- Reflec- Reductanoe Number tance tton tntsnee tlon in Sample before selling after reflec atter reflecso cyclessoiling tance, laundertanee,

percent lug percent Untreated 92. 5 2 49. 6 46. 5 92. 7 BaSOi Ahcovel RCMC 99.2 4 65.7 33.8 96.0 3. 99. 0 4 64. 6 34. 8 81. 1 18. 96.7 4 59.738.7 58.0 40. 96. 0 4 58. 5 40. 1 60. 2 37.

EXAMPLE v Raw stock viscose rayon fibers were treated with a 10%solution of barium chloride in a raw stock pressure dyeing machine forminutes at 140 F., extracted to 80% pick-up and dried, leaving-8% bariumchloride deposited. Thefibers were processed into yarn and sewn into cutpile rugs on a cotton backing. They were then treated with sodiumsulfate,.Ahcovel R and sodium carboxymethyl'cellulose, magnesium sulfateand acetic acid in the same percentages and manner as described inExample II. Solids pick-up was 7.61% barium sulfate, 0.5% Ahcovcl R and0.5% carboxymethyl cellulose.

The materials treated according to my process exhibit excellentsoil-resistant properties which are retained through numerous.launderings and dry cleanings. Such soil as does accumulate after anextended period of time is readily and substantially completely removedby ordinary laundering or dry cleaning procedures. The

treatment imparts excellent luster and improved texture and feel to'thematerials.

Table I summarizes characteristic results obtained with my treatment anddemonstrates the great improvement in luster and soil resistance. Thetable also shows the marked superiority of the treatment comprising acombination of the barium sulfate, cationic fatty amide softening agentand carboxymethyl cellulose in terms of soilresistance andlaunderability as compared with the use of barium sulfate alone orbarium sulfate with either the softening agent orcarboxymethylcellulose.

After only two soiling cycles the untreated cut pile rug lost 46.5% ofits reflectance whereas the rug subjected to the full treatmentlost-only 33.8% of its original improved reflectance after four'soilingcycles. Where the rug treated with barium sulfate alone showed areduction in reflectance of 37.3% after laundering, the fully treatedrug showed a reduction of only 3.2% and the actual reflectance valueafter. laundering was higher than that of the original unsoiled control.

The floor coverings treated in the series of tests given in Table Icomprised white, cut pile rugs made of 8 denier, 1%; inch bright viscoserayon sewn on a white cotton backing. The proportions of treating agentsintroduced were as follows:

Percent B380 10.0 Ahcovel R 0.3 Carboxymethyl cellulose 0.1

The various treating agents were introduced in a manner similar to thosedisclosed in the preceding examples.

1. A method for imparting soil resistance to textilematerial whichcomprises separately impregnating the material with an aqueous solutionofa water. soluble barium compound and an aqueous solution of a watersoluble sulfate, said solutions being applied in any desired sequence,whereby at least about 2% barium sulfate by weight of the material isdeposited in the material, impregnating the material with a higher fattyacid amide softening agent in aqueous solution, said softening agentbeingselected from the group consisting of cationic compounds andpotentially cationic compounds which form cationic acid salts uponacidification and sodium carboxymethyl cellulose in aqueous solution,exhausting the softening agent and carboxymethyl cellulose onto thematerial by adding an acid salt in sufficient amount to reduce the pH ofthe solution to about 6.5 to 7.0 and then adding'an organic acid insuflicient amount to further reduce the pH to about 6.0 to 6.5, saidsoftening agent being introduced into the material in an amountcomprising at least about 0.1% of weight of the material and saidcarboxymethyl cellulose being introduced into the material in an amountcomprising at least about 0.1% by weight of the material, and thendrying the material.

2. The process of claim 1 in which the cationic softening agent is thereaction product of polybasic organic acid with dialkylol substitutedcarbamido compound carrying side chains containing a polyamino acidradical.

3. The process of claim 2 in which the textile material is a pile fabriccontaining fibers selected from the class consisting of vegetable andsynthetic fibers.

4. The process of claim 1 in which the acid salt is magnesium sulfateand. the organic acid is acetic acid.

5. The proess of claim 4 in which the softening agent is introduced intothe material in an amount comprising at least about 0.25% by weight ofthe material.

6. The process of claim 5 in which the barium sulfate is introduced inan amount comprising at least about 3% by weight of the material.

7. The process of claim 6 in which the textile material is a pile fabriccontaining fibers selected from the class consisting of vegetable andsynthetic fibers.

8. A method for imparting soil resistance to textile materialwhichcomprises separately impregnating the material with an aqueous solutionof a water soluble barium salt and an aqueous solution of a watersoluble sulfate, said solutions being applied in any desired sequence,the material being dried between application of said first and secondsolutions, whereby at least about 2% barium sulfate by weight of thematerial is deposited in the material, including in the second reactingsolution a higher fatty acid amide softening agent selected from thegroup consisting of cationic compounds and potentially cationiccompounds which form acid salts upon acidfication and sodiumcarboxymethyl cellulose, adding to-said second solution afterprecipitation of the barium sulfate an acid salt in amount sufficient toreduce the pH of the solution to about 6.5 to 7.0 and then adding tosaid second solution an organic acid in amount sufficient to furtherreduce the pH to about 6.0 to 6.5, the softening agent and carboxymethylcellulose each being introduced into the material in an amountcomprising at least about 0.1% by weight of the material and then dryingthe material.

9. The method of claim 8 in which the textile material contains fibersselected from the group consisting of vegetable and synthetic fibers andthe softening agent is the reaction product of polybasic vorganic acidwith dialkylol substituted carbamido compound carrying side chainscontaining a polyamino acid radical.

10. The method of claim 9 in which the softening agentis. introducedinto the materialin an amount comprising at least about 0.25% by weightof the material and the barium-sulfate in an amount-comprising at leastabout 3% by weight of the material.

11. Textile material, characterized by improved soil resistantproperties, impregnated with finely divided-barium sulfate deposited insitu in amount at least about 2% by weight of the material, at leastabout 0.1% by weight of the material of a cationic softening agent andat least about 0.1% .by weight of the material carboxymethyl cellulose.

12. The product of claim 11 in which the cationic softening agent is ahigher fatty acid amide.

13. The product of claim 12 in which the textile material-containsfibers selected from the class consisting of vegetable andsynthetic'fibers.

14. The product of claim 13 in which the textile material is a pilefabric.

15. The product of claim 11 in which the softening agent'is the reactionproduct of polybasic organic acid with dialkylol substituted carbamidocompound carrying sidechains containing a polyamino acid radical and ispresent in an amount comprising at least about 0.25% by weight of thematerial.

16. The product of claim 15 in which the barium sulfate is present in anamount comprising at least about 3% by weight of the material.

'17. A method for imparting soil resistance to textile material whichcomprises separately impregnating the material with an aqueous solutionof a water soluble barium compound and an aqueous solution of a watersoluble sulfate, said solutions being applied in any desired sequence,whereby at least about 2% barium sulfate by weight of the material isdeposited in the material, impregnating the material with a higher fattyacid amide softening agent in aqueous solution, said softening agentbeing selected from the group consisting of cationic con" pounds and.potentially cationic compounds which form cationic acid salts uponacidification and an alkali metal salt of carboxyrnethyl cellulose inaqueous solution, exhausting the softening agent and carboxymethylcelluloze onto the material by acidifying the solution, said softeningagent and said carboxymethyl cellulose each being introduced into thematerial in an amount comprising at least about 0.1% by weight of thematerial and then drying the material.

18. A method for imparting soil resistance to textile material whichcomprises separately impregnating the material with an aqueous solutionof a water soluble barium compound and an aqueous solution of a watersoluble sulfate, said solutions being applied in any desired sequence,the material being dried between application of said first and secondsolutions, whereby at least about 3% barium sulfate by weight of thematerial is deposited in the material, impregnating the material with ahigher fatty acid amide softening agent in aqueous solution, saidsoftening agent being selected from the group consisting of cationiccompounds and potentially cationic compounds which form cationic acidsalts upon acidification and an alkali metal salt of carboxymethylcellulose in aqueous solution, exhausting the softening agent andcarboxymethyl cellulose onto the material by gradually acidifying thesolution first by addition of an acid salt and then by addition of anorganic acid, said softening agent being introduced into the material inan amount comprising at least about 0.25% by weight of the material andsaid carboxymethyl cellulose being introduced into the material in anamount comprising at least about 0.1% by weight of the material and thendrying the material.

19. A method for imparting soil resistance to textile material whichcomprises separately impregnating the material with an aqueous solutionof a water soluble barium compound and an aqueous solution of a watersoluble sulfate, said solutions being applied in any desired sequence,whereby at least about 2% barium sulfate by weight of the material isdeposited in the material, impregnating the material with a softeningagent in aqueous solution, said softening agent being selected from thegroupconsisting of cationiccompounds and potentially cationic compoundswhich form cationic acid salts upon acidification, and an alkali metalsalt of carboxymethyl cellulose in aqueous solution, exhausting thesoftening agent and earboxymethyl cellulose onto the material byacidifying to a maximum pH of about 6.5, said softening agent and saidcarboxymethyl cellulose each being introduced in an amount comprising atleast about 0.1% by weight of the material, and then drying thematerial.

20. The process of claim 19 in which the softening agent is a higherfatty acid amide.

21. A method for imparting soil resistance to textile material whichcomprises separately impregnating the material with an aqueous solutionof a water soluble barium compound and an aqueous solution of a watersoluble sulfate, said solutions being supplied in any desired sequence,whereby at least about 2% barium sulfate by weight of the material isdeposited in the material, impregnating the material with a softeningagent in aqueous solution, said softening agent being selected from thegroup consisting of cationic compounds and potentially cationiccompounds which form cationic acid salts upon acidification, and analkali metal salt of carboxymethyl cellulose in aqueous solution,exhausting the softening agent and carboxymethyl cellulose onto thematerial by adding first an acid salt and then an organic acid insufficient amount to reduce the pH to a maximum of about 6.5 and thendrying the material.

22. The process of claim 21 in which the softening agent is a higherfatty acid amide and the carboxymethyl cellulose is sodium carboxymethylcellulose.

References Cited in the file of this patent UNITED STATES PATENTS152,903 Gender et al. .luly 14, 1874 2,410,788 Morgan et al. Nov. 5,1946 2,570,750 Bauer Oct. 9, 1951 2,693,247 Kingsford Nov. 2, 19542,701,218 Nickerson Feb. 1, 1955 FOREIGN PATENTS 705,672 Great BritainMar. 17, 1954 (Other references on following page) 9 omen REFERENCESMollient: Silk Journal and Rayon World, May 1943, pp. 27, 28 and 30;117-1395.

Compton et al.: Soiling and Soil Retention. in Textile Fibers, Ind. andEng. Chem, vol. 45, No. 3, pp. 597-602.

Feuell: Desoiling Properties of Carboxymethyl Cellulose," Journal ofTextile Institute, vol. 40, No. 8, August 1949, 8-137, pp. T-523-525.

Bayley et al.: The Influence of Sodium Carbonymethylcellul'ose on thesuspending Power of Build Soap 10 Solutions, Textile Research Journal,July 1950, pp. 510- 513; 8-137.

Untermohlen et aL: Improvement of Cotton Cloth in Resistance to Soilingand in Ease of Washing, Textile 5 Research Journal, July 1951, pp.510-521.

Pollok: Sodium Carboxymethylcellulose, Journal Textile Institute, vol.343, No. 4, April 1952, p. A-256;

Names, 1953. Pp. 17 and 1s.

1. A METHOD FOR IMPARTING SOIL RESISTANCE TO TEXTILE MATERIAL WHICHCOMPRISES SEPARATELY IMPREGNATING THE MATERIAL WITH AN AQUEOUS SOLUTIONOF A WATER SOLUBLE BARIUM COMPOUND AND AN AQUEOUS SOLUTION OF A WATERSOLUBLE SULFATE, SAID SOLUTIONS BEING APPLIED IN ANY DESIRED SEQUENCE,WHEREBY AT LEAST ABOUT 2% BARIUM SULFATE BY WEIGHT OF THE MATERIAL ISDEPOSITED IN THE MATERIAL, IMPREGNATING THE MATERIAL WITH A HIGHER FATTYACID AMIDE SOFTENING AGENT IN AQUEOUS SOLUTION, SAID SOFTENING AGENTBEING SELECTED FROM THE GROUP CONSISTING OF CATIONIC COMPOUNDS ANDPOTENTIALLY CATIONIC COMPOUNDS WHICH FORM CATIONIC ACID SALTS UPONACIDIFICATION AND SODIUM CARBOXYMETHYL CELLULOSE IN AQUEOUS SOLUTION,EXHAUSTING THE SOFTENING AGENT AND CARBOXYMETHYL CELLULOSE ONTO THEMATERIAL BY ADDING AN ACID SALT IN SUFFICIENT AMOUNT OF REDUCE THE PH OFTHE SOLUTION TO ABOUT 6.5 TO 7.0 AND THEN ADDING AN ORGANIC ACID INSUFFICIENT AMOUNT TO FURTHER REDUCE THE PH TO ABOUT 6.0 TO 6.5 SAIDSOFTENING AGENT BEING INTRODUCED INTO THE MATERIAL IN AN AMOUNTCOMPRISING AT LEAST ABOUT 0.1% OF WEIGHT OF THE MATERIAL AND SAIDCARBOXYMETHYL CELLULOSE BEING INTRODUCED INTO THE MATERIAL IN AN AMOUNTCOMPRISING AT LEAST ABOUT 0.1% BY WEIGHT OF THE MATERIAL, AND THENDRYING THE MATERIAL.